A starting control method of a multi-connected air conditioner and a multi-connected air conditioner

Abstract

The application discloses a starting control method of a multi-connected air conditioner and the multi-connected air conditioner, and relates to the technical field of air conditioners. The starting control method of the multi-connected air conditioner comprises the following steps: when the multi-connected air conditioner is started for heating, the outdoor environment temperature is detected; when the outdoor environment temperature is lower than a first preset temperature, the compressor exhaust gas is controlled to enter a first target indoor unit in a running state for heat exchange after passing through a first four-way valve, and the refrigerant after heat exchange in the first target indoor unit is controlled to flow back to the compressor after passing through the first four-way valve; the compressor exhaust gas is controlled to enter a second target indoor unit in a shutdown state after passing through the first four-way valve, and the refrigerant flowing through the second target indoor unit is controlled to flow back to the compressor after passing through a second four-way valve. The application can guarantee the normal starting operation of the starting indoor unit, improve the heating effect of the starting indoor unit, increase the refrigerant circulation amount in the system during the starting process, rapidly improve the exhaust gas superheat degree of the compressor, and improve the reliability of the starting of the compressor.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of air conditioning, in particular to a starting control method of a multi-connected air conditioner and the multi-connected air conditioner. BACKGROUND

[0002] With the improvement of people's living standards, the use of air conditioners is becoming more and more widespread, and ultra-low temperature heating has become a use scenario of air conditioners, and there is a higher requirement for the ultra-low temperature starting performance of air conditioners. When the existing air conditioner starts in the scene of ultra-low temperature heating, the compressor overheat degree is established slowly due to the low ambient temperature, and the compressor is prone to oil shortage during the starting process, which greatly affects the reliability of the compressor starting. SUMMARY

[0003] To solve the above problems, the present application provides a starting control method of a multi-connected air conditioner and the multi-connected air conditioner, which can ensure the normal starting operation of the starting indoor unit, improve the heating effect of the starting indoor unit, and increase the refrigerant circulation amount in the system during the starting process, quickly improve the discharge overheat degree of the compressor, and improve the reliability of the compressor starting.

[0004] According to an embodiment of the present application, a starting control method of a multi-connected air conditioner is provided, the multi-connected air conditioner comprising an outdoor unit and multiple indoor units, the outdoor unit comprising a first four-way valve and a second four-way valve, the starting control method of the multi-connected air conditioner comprising: when the multi-connected air conditioner starts heating, detecting the outdoor ambient temperature; when the outdoor ambient temperature is lower than a first preset temperature, controlling the compressor discharge to enter a first target indoor unit in a running state through the first four-way valve for heat exchange, and controlling the refrigerant after heat exchange in the first target indoor unit to flow back to the compressor through the first four-way valve; controlling the compressor discharge to enter a second target indoor unit in a shutdown state through the first four-way valve, and controlling the refrigerant flowing through the second target indoor unit to flow back to the compressor through the second four-way valve.

[0005] By adopting the above technical solution, when the multi-connected air conditioner is in a low temperature heating scene, the refrigerant is controlled to pass through the first four-way valve and the first target indoor unit in turn, and the refrigerant flowing out of the first target indoor unit is controlled to flow back to the compressor through the first four-way valve, so as to ensure the normal starting operation of the starting indoor unit. By controlling the refrigerant to pass through the first four-way valve, the second target indoor unit and the second four-way valve in turn and flow back to the compressor, part of the heat can be obtained from the indoor unit that is not running, the refrigerant circulation amount in the system can be increased, the discharge overheat degree of the compressor can be quickly improved, and the reliability of the compressor starting is improved.

[0006] Preferably, the first port of the first four-way valve is connected with the exhaust port of the compressor, the second port of the first four-way valve is connected with one end of the heat exchanger of the indoor unit through the gas pipe, the other end of the heat exchanger of the indoor unit is connected with the third port of the first four-way valve through the liquid pipe, the first electronic expansion valve is arranged on the liquid pipe between the indoor unit and the third port, the fourth port of the first four-way valve is connected with the suction port of the compressor through the gas branch, the first port of the first four-way valve is in internal communication with the second port, and the third port of the first four-way valve is in internal communication with the fourth port.

[0007] The step of controlling the compressor exhaust to enter the first target indoor unit in the running state through the first four-way valve for heat exchange and controlling the refrigerant after heat exchange in the first target indoor unit to flow back to the compressor through the first four-way valve comprises the following steps.

[0008] The first electronic expansion valve corresponding to the first target indoor unit is controlled to be opened, so that the compressor exhaust enters the first target indoor unit through the first four-way valve and the gas pipe, and flows back to the compressor through the first electronic expansion valve on the liquid pipe and the first four-way valve.

[0009] By adopting the above technical scheme, the first electronic expansion valve corresponding to the first target indoor unit in the open running state is controlled to be opened, so that the refrigerant enters the first target indoor unit in the open running state, to quickly heat and improve the indoor environment temperature, thereby ensuring the normal heating start of the open indoor unit and improving the user experience.

[0010] Preferably, the indoor unit comprises a first heat exchanger, a second heat exchanger and a second electronic expansion valve, the first electronic expansion valve is connected with the first heat exchanger through a pipeline, one end of the second electronic expansion valve is connected with the second heat exchanger through a pipeline, and the other end of the second electronic expansion valve is connected with the first electronic expansion valve and the first heat exchanger through a pipeline respectively; the starting control method of the multi-connected air conditioner further comprises the following steps.

[0011] The second electronic expansion valve corresponding to the first target indoor unit is controlled to be closed, so that the refrigerant flowing into the first target indoor unit passes through the first heat exchanger and then flows back to the compressor through the first electronic expansion valve on the liquid pipe and the first four-way valve.

[0012] By adopting the above technical scheme, the second electronic expansion valve corresponding to the first target indoor unit in the open running state is controlled to be closed, to ensure that the refrigerant quickly flows back to the compressor, and at the same time, the refrigerant can only enter one heat exchanger for heat exchange, thereby ensuring that the refrigerant in the heat exchanger is sufficient for normal heating start and improving the heating speed of the indoor unit.

[0013] Preferably, the second heat exchanger is further connected to the first interface of the second four-way valve through the high-low pressure pipeline, the second interface of the second four-way valve is connected to the suction port of the compressor through the gas distributor, and the first interface of the second four-way valve is in internal communication with the second interface.

[0014] The step of controlling the compressor exhaust to enter the second target indoor unit in the shutdown state through the first four-way valve and controlling the refrigerant flowing through the second target indoor unit to flow back to the compressor through the second four-way valve comprises:

[0015] The first electronic expansion valve corresponding to the second target indoor unit is controlled to be closed, and the second electronic expansion valve corresponding to the second target indoor unit is controlled to be opened, so that the compressor exhaust enters the first four-way valve and then flows into the first heat exchanger through the gas pipe, and sequentially flows back to the compressor through the second electronic expansion valve, the second heat exchanger, the high-low pressure pipeline and the second four-way valve.

[0016] By adopting the above technical solution, in the low-temperature heating startup stage of the multi-connected air conditioner, the second target indoor unit in the closed state is controlled to circulate refrigerant with the compressor, so that the exhaust superheat of the compressor can be quickly improved, the system oil level is ensured, the risk of lack of oil of the unit is reduced, and the startup reliability of the compressor is improved.

[0017] Preferably, the second four-way valve further comprises a third interface and a fourth interface, the third interface is connected to the exhaust port of the compressor, and the fourth interface is connected to the pipeline between the second interface and the gas distributor, and the startup control method further comprises:

[0018] determining whether the multi-connected air conditioner reaches a stable running state;

[0019] When the multi-connected air conditioner reaches the stable running state, the first electronic expansion valve corresponding to the first target indoor unit is controlled to be opened, the second electronic expansion valve corresponding to the first target indoor unit is controlled to be opened, and the second four-way valve is controlled to reverse, so that the first interface is in internal communication with the third interface, and the second interface is in internal communication with the fourth interface.

[0020] By adopting the above technical solution, after the multi-connected air conditioner reaches the stable running state, the compressor exhaust is divided into two paths to circulate refrigerant with two heat exchangers in the first target indoor unit in the running state, so that the refrigerant circulation speed and the total refrigerant flow in the indoor unit are improved, the heating speed of the indoor unit is improved, and the heating comfort of the indoor unit is ensured.

[0021] Preferably, the startup control method further comprises:

[0022] When the multi-connected air conditioner reaches a stable running state, the first electronic expansion valve corresponding to the second target indoor unit is controlled to open to a preset minimum opening degree, and the second electronic expansion valve corresponding to the second target indoor unit is controlled to open to a preset minimum opening degree.

[0023] By adopting the technical scheme, when the multi-connected air conditioner reaches a stable running state, the first electronic expansion valve and the second electronic expansion valve corresponding to the second target indoor unit in the closed state are both controlled to open to a preset minimum opening degree, so that the second target indoor unit in the closed state still maintains a small refrigerant circulation on the basis of not affecting the heating demand of the first target indoor unit in the running state, and the situation of refrigerant deposition is avoided.

[0024] Preferably, the step of judging whether the multi-connected air conditioner reaches a stable running state comprises:

[0025] The exhaust temperature and the high-pressure saturation temperature of the compressor are monitored, the temperature difference between the exhaust temperature and the high-pressure saturation temperature is calculated, and when the temperature difference is greater than or equal to a second preset temperature, it is determined that the multi-connected air conditioner reaches a stable running state.

[0026] By adopting the technical scheme, the temperature difference between the exhaust temperature and the high-pressure saturation temperature of the multi-connected air conditioner is monitored, and the size of the temperature difference is judged, so that whether the exhaust superheat degree reaches the running requirement can be judged, and then whether the multi-connected air conditioner reaches a stable running state can be judged, and the accuracy and rationality of the running state judgment of the multi-connected air conditioner are improved.

[0027] According to the embodiment of the application, another aspect provides a multi-connected air conditioner, comprising an outdoor unit, a plurality of indoor units and a controller, the outdoor unit comprises a first four-way valve and a second four-way valve, the controller comprises a computer readable storage medium storing a computer program and a processor, and when the computer program is read and run by the processor, the method of any one of the first aspect is implemented.

[0028] Preferably, the first port of the first four-way valve is connected with the exhaust port of the compressor, the second port of the first four-way valve is connected with one end of the heat exchanger of the indoor unit through a gas pipe, the other end of the heat exchanger of the indoor unit is connected with the third port of the first four-way valve through a liquid pipe, the first electronic expansion valve is arranged on the liquid pipe between the indoor unit and the third port, the fourth port of the first four-way valve is connected with the suction port of the compressor through a gas branch, the first port of the first four-way valve is in internal communication with the second port, and the third port of the first four-way valve is in internal communication with the fourth port.

[0029] The indoor unit comprises a first heat exchanger, a second heat exchanger and a second electronic expansion valve, the first electronic expansion valve is connected with the first heat exchanger through a pipeline, one end of the second electronic expansion valve is connected with the second heat exchanger through a pipeline, and the other end of the second electronic expansion valve is connected with the first electronic expansion valve and the first heat exchanger through a pipeline respectively.

[0030] Preferably, the second four-way valve comprises a first interface, a second interface, a third interface and a fourth interface; the second heat exchanger is connected with the first interface through a high-low pressure pipeline, the second interface is connected with the suction port of the compressor through the gas distribution, the third interface is connected with the exhaust port of the compressor, and the fourth interface is connected to the pipeline between the second interface and the gas distribution;

[0031] When the multi-connected air conditioner is started, the first interface and the second interface are in internal communication, and the third interface and the fourth interface are in internal communication;

[0032] When the multi-connected air conditioner reaches a stable running state, the first interface and the third interface are in internal communication, and the second interface and the fourth interface are in internal communication.

[0033] The application has the following beneficial effects: when the multi-connected air conditioner is in a low-temperature heating scene, the refrigerant is controlled to pass through the first four-way valve and the first target indoor unit in turn, and the refrigerant flowing out of the first target indoor unit is caused to flow back to the compressor through the first four-way valve, so as to ensure the normal starting and running of the starting indoor unit; by controlling the refrigerant to pass through the first four-way valve, the second target indoor unit and the second four-way valve in turn and flow back to the compressor, part of the heat in the indoor unit which is not running can be obtained, the refrigerant circulation amount in the system can be increased, the exhaust superheat degree of the compressor can be quickly improved, and the reliability of the starting of the compressor is improved. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only exemplary, and for those skilled in the art, other drawings can be obtained from the provided drawings without creative labor.

[0035] The structures, proportions, sizes, etc. shown in the specification are only used to cooperate with the content disclosed in the specification, to be understood and read by those skilled in the art, and do not define the limiting conditions for the implementation of the application, so they do not have technical significance. Any modification of structure, change of proportion relationship or adjustment of size, without affecting the effect and purpose that can be achieved by the application, should still fall within the scope covered by the disclosed technical content.

[0036] Figure 1 A structure schematic diagram of a multi-connected air conditioner provided by the present application;

[0037] Figure 2 A flow chart of a starting control method of a multi-connected air conditioner provided by the present application;

[0038] Figure 3 A refrigerant circulation schematic diagram in a starting stage of a multi-connected air conditioner provided by the present application;

[0039] Figure 4 A refrigerant circulation schematic diagram in a stable running state of a multi-connected air conditioner provided by the present application. DETAILED DESCRIPTION

[0040] The embodiments of the present application will be described in detail by the following specific examples, and other advantages and effects of the present application can be easily understood by those skilled in the art from the contents disclosed in the specification. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0041] In order to make the above objectives, characteristics and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the drawings.

[0042] The present embodiment provides a multi-connected air conditioner, comprising an outdoor unit, multiple indoor units and a controller, the controller comprising a computer readable storage medium storing a computer program and a processor, and the computer program is read and run by the processor to realize the starting control method of the multi-connected air conditioner provided by the following embodiments.

[0043] Referring to a structure schematic diagram of a multi-connected air conditioner as shown in Figure 1 The outdoor unit comprises a first four-way valve 11, a second four-way valve 12, a compressor 13, an outdoor heat exchanger 14 and a gas distributor 15. The first port a1 of the first four-way valve 11 is connected with the exhaust port of the compressor 13. The second port a2 of the first four-way valve 11 is connected with one end of the heat exchanger of the indoor unit through the gas pipe 16. The other end of the heat exchanger of the indoor unit is connected with the third port a3 of the first four-way valve 11 through the liquid pipe 17. The first electronic expansion valve f1 is arranged on the liquid pipe 17 between the indoor unit and the third port a3. The fourth port a4 of the first four-way valve 11 is connected with the suction port of the compressor 13 through the gas distributor 15. The first port a1 and the second port a2 of the first four-way valve 11 are communicated in the four-way valve. The third port a3 and the fourth port a4 of the first four-way valve 11 are communicated in the four-way valve.

[0044] As shown in Figure 1As shown, each indoor unit includes a first heat exchanger n1, a second heat exchanger n2, and a second electronic expansion valve f2, the first electronic expansion valve f1 is connected with the first heat exchanger n1 through a pipeline, one end of the second electronic expansion valve f2 is connected with the second heat exchanger n2 through a pipeline, and the other end of the second electronic expansion valve f2 is connected with the first electronic expansion valve f1 and the first heat exchanger n1 through a pipeline respectively.

[0045] The second four-way valve 12 includes a first interface b1, a second interface b2, a third interface b3, and a fourth interface b4; the second heat exchanger 12 is connected with the first interface b1 through a high-low pressure pipeline 18, the second interface b2 is connected with a suction port of the compressor 13 through a gas distribution 15, the third interface b3 is connected with a discharge port of the compressor, and the fourth interface b4 is connected to a pipeline between the second interface b2 and the gas distribution 15.

[0046] When the multi-connected air conditioner starts, the first interface b1 and the second interface b2 are in internal communication, and the third interface b3 and the fourth interface b4 are in internal communication; when the multi-connected air conditioner reaches a stable running state, the second four-way valve 12 is controlled to reverse, so that the first interface b1 and the third interface b3 are in internal communication, and the second interface b2 and the fourth interface b4 are in internal communication.

[0047] In an embodiment, the controller is configured to, when the multi-connected air conditioner starts, control the first electronic expansion valve corresponding to the first target indoor unit in the open running state to be opened, and control the second electronic expansion valve corresponding to the first target indoor unit to be closed; control the first electronic expansion valve corresponding to the second target indoor unit in the closed state to be closed, and control the second electronic expansion valve corresponding to the second target indoor unit to be opened.

[0048] In an embodiment, the controller is further configured to, when the multi-connected air conditioner reaches a stable running state, control the first electronic expansion valve corresponding to the first target indoor unit in the open running state to be opened, and control the second electronic expansion valve corresponding to the first target indoor unit to be opened; control the first electronic expansion valve corresponding to the second target indoor unit in the closed state to be opened to a preset minimum opening degree, and control the second electronic expansion valve corresponding to the second target indoor unit to be opened to a preset minimum opening degree.

[0049] The embodiment provides a starting control method of a multi-connected air conditioner, which can be applied to the multi-connected air conditioner provided in the above embodiment. As shown in a starting control method flow chart of the multi-connected air conditioner, Figure 2 The method mainly includes the following steps S202-S206:

[0050] Step S202: When the multi-connected air conditioner starts heating, the outdoor environment temperature is detected.

[0051] When the multi-connected air conditioner is started and the user sets the operation mode as the heating mode, the outdoor environment temperature is detected based on the temperature sensor in the outdoor unit.

[0052] Step S204: When the outdoor environment temperature is lower than the first preset temperature, the compressor exhaust is controlled to enter the first target indoor unit in the running state after passing through the first four-way valve for heat exchange, and the refrigerant after the heat exchange in the first target indoor unit is controlled to flow back to the compressor through the first four-way valve.

[0053] The first preset temperature can be a temperature that easily leads to the risk of starting the compressor without oil. When the outdoor environment temperature is lower than the first preset temperature, it indicates that the multi-connected air conditioner is in a low-temperature heating start operation. Considering the low high-pressure, small compressor load, small heat generation, and large compressor heat dissipation when starting in an ultra-low temperature environment, the exhaust temperature is low, which affects the slow establishment of the exhaust superheat degree, and the insufficient exhaust superheat degree will increase the system oil discharge rate. Therefore, in the ultra-low temperature heating start, the low outdoor temperature easily leads to low system evaporation pressure, i.e., small compressor suction volume, and it is difficult for the discharged oil to be sucked back into the compressor, thereby causing a large system oil shortage risk.

[0054] Each indoor unit in the open running state is obtained and recorded as a first target indoor unit. The electronic expansion valve of each first target indoor unit is controlled to make the circulation path of the refrigerant be compressor→first four-way valve→first target indoor unit→first four-way valve→compressor, so that the first target indoor unit in the open running state can quickly raise the indoor temperature and ensure the normal heating operation of each open state indoor unit.

[0055] Step S206: The compressor exhaust is controlled to enter the second target indoor unit in the shutdown state after passing through the first four-way valve, and the refrigerant flowing through the second target indoor unit is controlled to flow back to the compressor through the second four-way valve.

[0056] Each indoor unit in the closed state is obtained and recorded as a second target indoor unit. The electronic expansion valve of each second target indoor unit in the closed state is controlled to make the circulation path of the refrigerant be compressor→first four-way valve→second target indoor unit→second four-way valve→compressor. By circulating the refrigerant in the second target indoor unit into the compressor, the refrigerant circulation amount of the compressor can be improved. Since the exhaust temperature of the compressor is obtained by the compressor work, when the refrigerant in the second target indoor unit is circulated with the refrigerant in the compressor, the high-pressure is higher and the compressor operating load is larger, which can improve the rising speed of the exhaust temperature and the rising speed of the exhaust superheat degree, thereby reducing the risk of system oil shortage.

[0057] The starting control method of the multi-connected air conditioner provided in the embodiment can ensure normal starting operation of the starting indoor unit by controlling the refrigerant to sequentially pass through the first four-way valve and the first target indoor unit, and making the refrigerant flowing out of the first target indoor unit flow back to the compressor through the first four-way valve when the multi-connected air conditioner is in a low-temperature heating scene. By controlling the refrigerant to sequentially pass through the first four-way valve, the second target indoor unit and the second four-way valve and flow back to the compressor, part of the heat in the indoor unit that is not in operation can be obtained, the refrigerant circulation amount in the system can be increased, the exhaust superheat of the compressor can be quickly improved, and the reliability of the starting of the compressor is improved.

[0058] In one embodiment, the embodiment provides an implementation of controlling the compressor exhaust to enter the first target indoor unit in operation to exchange heat after passing through the first four-way valve, and controlling the refrigerant after heat exchange in the first target indoor unit to flow back to the compressor through the first four-way valve. The implementation can be specifically executed according to the following steps:

[0059] Step (1): The first electronic expansion valve corresponding to the first target indoor unit is controlled to be opened, so that the compressor exhaust passes through the first four-way valve and the gas pipe to enter the first target indoor unit, and flows back to the compressor through the first electronic expansion valve on the liquid pipe and the first four-way valve.

[0060] Referring to the refrigerant circulation schematic diagram of the multi-connected air conditioner in the starting stage as shown in Figure 3 After the multi-connected air conditioner is started and operated in low temperature, the first electronic expansion valve f1 corresponding to the first target indoor unit is controlled to be opened. Assuming that each indoor unit is the first target indoor unit in the opened and operated state, the compressor exhaust passes through the first four-way valve 11, the gas pipe 16, each first target indoor unit in the opened and operated state, the first electronic expansion valve f1, the liquid pipe 17, the first four-way valve 11 and the compressor 13, to ensure the heating starting operation of each first target indoor unit in the opened and operated state.

[0061] By controlling the first electronic expansion valve corresponding to the first target indoor unit in the opened and operated state to be opened, the refrigerant can enter the first target indoor unit in the opened and operated state, to quickly heat and improve the indoor environment temperature, ensure the normal heating starting of the opened indoor unit, and improve the user experience.

[0062] Step (2): The second electronic expansion valve corresponding to the first target indoor unit is controlled to be closed, so that the refrigerant flowing into the first target indoor unit passes through the first heat exchanger and then flows back to the compressor through the first electronic expansion valve on the liquid pipe and the first four-way valve.

[0063] As shown in Figure 3As shown, the first target indoor unit in the open state is controlled to close the second electronic expansion valve f2 corresponding to the first target indoor unit, so that the refrigerant flows back to the compressor through the first electronic expansion valve f1 and the first four-way valve 11 on the liquid pipe, realizing the refrigerant circulation. By controlling the second electronic expansion valve corresponding to the first target indoor unit in the open state to be closed, the refrigerant can quickly flow back to the compressor, and the refrigerant can only enter one heat exchanger to exchange heat, ensuring that the refrigerant in the heat exchanger is sufficient to start heating normally, and the heating speed of the indoor unit is improved.

[0064] In one embodiment, the embodiment provides a specific implementation of controlling the compressor exhaust to enter the second target indoor unit in the shutdown state after passing through the first four-way valve, and controlling the refrigerant flowing through the second target indoor unit to flow back to the compressor through the second four-way valve:

[0065] The first electronic expansion valve corresponding to the second target indoor unit is controlled to be closed, and the second electronic expansion valve corresponding to the second target indoor unit is controlled to be opened, so that the compressor exhaust enters the first four-way valve and then flows into the first heat exchanger through the gas pipe, and then flows back to the compressor through the second electronic expansion valve, the second heat exchanger, the high-low pressure pipe and the second four-way valve in turn.

[0066] After the low-temperature heating of the multi-split air conditioner is started, for each second target indoor unit in the closed state, the first electronic expansion valve f1 corresponding to each second target indoor unit is controlled to be closed, and the second electronic expansion valve f2 corresponding to the second target indoor unit is controlled to be opened, as shown in Figure 3 As shown, assuming that each indoor unit is a second target indoor unit in the closed state, the compressor exhaust enters the first four-way valve 11→ the gas pipe 16→ the first heat exchanger n1 of the second target indoor unit→ the second electronic expansion valve f2→ the second heat exchanger n2→ the high-low pressure pipe 18→ the second four-way valve 12→ the compressor 13.

[0067] By controlling the second target indoor unit in the closed state and the compressor to circulate the refrigerant during the low-temperature heating startup of the multi-split air conditioner, the exhaust superheat of the compressor can be quickly improved, the oil level of the system is ensured, the risk of oil shortage of the unit is reduced, and the startup reliability of the compressor is improved.

[0068] In one embodiment, the method provided by the embodiment further includes the following steps:

[0069] Step 1): Determine whether the multi-split air conditioner reaches a stable running state;

[0070] After the multi-split air conditioner is started and runs for a period of time, it is determined in real time whether the exhaust superheat of the multi-split air conditioner meets the control requirement. When the exhaust superheat of the multi-split air conditioner meets the control requirement, the multi-split air conditioner enters a stable running state.

[0071] In one specific implementation, the compressor's exhaust temperature and high-pressure saturation temperature are monitored, and the temperature difference between the exhaust temperature and the high-pressure saturation temperature is calculated. When the temperature difference is greater than or equal to a second preset temperature, the multi-split air conditioner is determined to have reached a stable operating state. The value of the aforementioned second preset temperature can be in the range of 8 to 12 degrees Celsius, with a preferred value of 10 degrees Celsius.

[0072] By monitoring the temperature difference between the exhaust temperature and the high-pressure saturation temperature of a multi-split air conditioner and determining the magnitude of this temperature difference, it is possible to determine whether the exhaust superheat has met the operating requirements, and thus whether the multi-split air conditioner has reached a stable operating state, thereby improving the accuracy and rationality of the judgment of the operating status of the multi-split air conditioner.

[0073] Step 2): When the multi-split air conditioner reaches a stable operating state, control the opening of the first electronic expansion valve corresponding to the first target indoor unit, control the opening of the second electronic expansion valve corresponding to the first target indoor unit, and control the reversal of the second four-way valve so that the first interface and the third interface are internally connected, and the second interface and the fourth interface are internally connected.

[0074] When the multi-split air conditioner reaches a stable operating state, it controls the reversing of the second four-way valve 12, as shown in the example. Figure 4 The diagram shows the refrigerant circulation in a multi-split air conditioner under stable operation. The first port b1 of the second four-way valve 12 is internally connected to the third port b3, and the second port b2 is internally connected to the fourth port b4. Controlling the opening of the first electronic expansion valve f1 corresponding to the first target indoor unit in the start-up state, and controlling the opening of the second electronic expansion valve f2 corresponding to the first target indoor unit, a portion of the compressor exhaust → first four-way valve 11 → gas pipe 16 → enters the first heat exchanger n1 of the first target indoor unit, where the condensed liquid refrigerant → first electronic expansion valve f1 → liquid pipe 17 → outdoor heat exchanger 14 → first four-way valve 11 → compressor, thus completing the refrigerant circulation.

[0075] like Figure 4 As shown, the other part of the compressor discharges → second four-way valve 12 → high and low pressure pipeline 18 → second heat exchanger n2 of the first target indoor unit → second electronic expansion valve f2 → first electronic expansion valve f1 → liquid pipe 17 → outdoor heat exchanger 14 → first four-way valve 11 → compressor, thus completing the refrigerant cycle.

[0076] After the multi-split air conditioner is running stably, the compressor exhaust is split into two paths to circulate refrigerant with the two heat exchangers in the first target indoor unit, which is in operation. This increases the refrigerant circulation speed and total refrigerant flow in the indoor unit, thereby improving the heating speed of the indoor unit and ensuring the heating comfort of the indoor unit.

[0077] Step 3): When the multi-connected air conditioner reaches a stable running state, the first electronic expansion valve corresponding to the second target indoor unit is controlled to open to a preset minimum opening degree, and the second electronic expansion valve corresponding to the second target indoor unit is controlled to open to a preset minimum opening degree.

[0078] When the multi-connected air conditioner reaches a stable running state, for the second target indoor unit in the closed state, the first electronic expansion valve and the second electronic expansion valve corresponding to the second target indoor unit are both opened, but the first electronic expansion valve and the second electronic expansion valve corresponding to the second target indoor unit are both operated at a preset minimum opening degree, and the preset minimum opening degree can be in the range of 20-70 pls.

[0079] A part of the compressor exhaust gas is guided to the first four-way valve 11, then to the gas pipe 16, then to the first heat exchanger n1 of the second target indoor unit, then to the first electronic expansion valve f1, then to the liquid pipe 17, then to the outdoor heat exchanger 14, then to the first four-way valve 11, and then to the compressor, and another part of the compressor exhaust gas is guided to the second four-way valve 12, then to the high-low pressure pipe 18, then to the second heat exchanger n2 of the second target indoor unit, then to the second electronic expansion valve f2, then to the first electronic expansion valve f1, then to the liquid pipe 17, then to the outdoor heat exchanger 14, then to the first four-way valve 11, and then to the compressor, so that the second target indoor unit in the closed state completes a small-flow refrigerant low-speed circulation.

[0080] By controlling the first electronic expansion valve and the second electronic expansion valve corresponding to the second target indoor unit in the closed state to open to a preset minimum opening degree when the multi-connected air conditioner reaches a stable running state, the second target indoor unit in the closed state still maintains a small refrigerant circulation without affecting the heating demand of the first target indoor unit in the running state, so that the situation of refrigerant deposition in the pipeline is avoided.

[0081] The starting control method of the multi-connected air conditioner provided in the embodiment can obtain part of the heat from the non-running indoor unit during ultra-low temperature heating startup, which is used to quickly increase the compressor exhaust superheat degree, ensures the reliability of the compressor, and enables the running indoor room to be quickly heated, thereby improving the heating comfort.

[0082] Corresponding to the starting control method of the multi-connected air conditioner provided in the above embodiment, the embodiment of the present application provides an example of applying the starting control method of the multi-connected air conditioner, which can be specifically executed according to the following steps:

[0083] Step 1: during the low-temperature heating startup phase of the multi-connected air conditioner:

[0084] The refrigerant circulation path of the first target indoor unit in the running state is: the compressor exhaust gas is guided to the first four-way valve, then to the gas pipe, then to the liquid refrigerant after condensation of each first target indoor unit in the opened state, then to the first electronic expansion valve, then to the liquid pipe, then to the first four-way valve, and then to the compressor, thereby completing the refrigerant circulation.

[0085] The refrigerant circulation path of the second target indoor unit in the non-operation state: the compressor exhaust gas enters the first four-way valve → the gas pipe → the liquid refrigerant after condensation in the first heat exchanger of the second target indoor unit in the non-operation state → the second electronic expansion valve → evaporates in the second heat exchanger → the high-low pressure pipe → the second four-way valve → the compressor, to complete the refrigerant circulation.

[0086] The exhaust gas superheat establishment process: the compressor exhaust gas temperature is obtained by the work of the compressor. When the high-pressure pressure is high, the compressor load is large, and the compressor work is more, the exhaust gas temperature rises fast at this time.

[0087] The high-pressure pressure is related to the evaporation pressure. When the outdoor environment temperature is low, the conventional operation is to ensure that heat can be absorbed from the external environment temperature. At this time, the refrigerant needs to be lower than the outdoor temperature to absorb the heat of the outdoor, so when the low pressure is low, the high-pressure pressure is low. The indoor environment temperature is usually higher than the outdoor environment temperature, so a higher evaporation temperature can be achieved to absorb heat from the non-operating room, so the low pressure is high, and the high-pressure pressure is also high.

[0088] Step 2, in the stable operation stage of the multi-connected air conditioner:

[0089] When the compressor exhaust gas superheat meets the control requirements (usually the exhaust gas temperature - high-pressure saturation temperature ≥ 10 degrees), the second four-way valve is controlled to reverse.

[0090] The second four-way valve is controlled to reverse, and the first electronic expansion valve and the second electronic expansion valve corresponding to the first target indoor unit in the operation state are both opened. The refrigerant circulation path of the first target indoor unit in the operation state: part of the compressor exhaust gas → the first four-way valve → the gas pipe → the liquid refrigerant after condensation in the first heat exchanger of the first target indoor unit → the first electronic expansion valve → the liquid pipe → the outdoor heat exchanger after evaporation → the first four-way valve → the compressor, to complete the refrigerant circulation; the other part of the compressor exhaust gas → the second four-way valve → the high-low pressure pipe → the second heat exchanger of the first target indoor unit after condensation → the second electronic expansion valve → the first electronic expansion valve → the liquid pipe → the outdoor heat exchanger after evaporation → the first four-way valve → the compressor, to complete the refrigerant circulation.

[0091] The refrigerant circulation path of the second target indoor unit in the non-operation state: part of the compressor exhaust gas → the first four-way valve → the gas pipe → the first heat exchanger of the second target indoor unit → the first electronic expansion valve → the liquid pipe → the outdoor heat exchanger after evaporation → the first four-way valve → the compressor; the other part of the compressor exhaust gas → the second four-way valve → the high-low pressure pipe → the second heat exchanger of the second target indoor unit after condensation → the second electronic expansion valve → the first electronic expansion valve → the liquid pipe → the outdoor heat exchanger after evaporation → the first four-way valve → the compressor, to complete the small flow of refrigerant low-speed circulation of the second target indoor unit in the closed state.

[0092] The embodiment also provides a computer readable storage medium, and the computer readable storage medium stores a computer program. The computer program is executed by a processor to implement each process of the starting control method of the multi-connected air conditioner and achieve the same technical effects. To avoid repetition, details are not described herein. The computer readable storage medium can be a read-only memory (ROM), a random access memory (RAM), a magnetic disk, an optical disk, or the like.

[0093] Of course, those skilled in the art can understand that all or part of the processes in the above method embodiments can be completed by instructing a control device through a computer, and the program can be stored in a computer readable storage medium. The program can include the processes of the above method embodiments when executed, and the storage medium can be a memory, a magnetic disk, an optical disk, or the like.

[0094] Although the present application is disclosed as above, the present application is not limited to this. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, and the protection scope of the present application should be defined by the scope defined by the claims.

[0095] Finally, it should be noted that, in this document, the terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of another identical element in the process, method, article or device including the element.

[0096] Each embodiment in the specification is described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same or similar parts between each embodiment can be referred to each other. For the multi-connected air conditioner disclosed by the embodiments, since it corresponds to the starting control method of the multi-connected air conditioner disclosed by the embodiments, the description is relatively simple, and the relevant parts can be referred to the method part.

[0097] The foregoing description of the disclosed embodiments enables a person skilled in the art to make or use the application. Numerous modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without the use of the inventive faculty. Therefore, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0098] While the application has been disclosed by reference to the above embodiments, other modifications, variations, and alternatives are also possible. Accordingly, the application should not be limited to what has been specifically shown and described hereinabove.

Claims

1. A startup control method of a multi-connected air conditioner, characterized by, The multi-connected air conditioner comprises an outdoor unit and multiple indoor units, the outdoor unit comprises a first four-way valve and a second four-way valve, and the starting control method of the multi-connected air conditioner comprises: When the multi-connected air conditioner is started for heating, the outdoor environment temperature is detected; When the outdoor environment temperature is lower than a first preset temperature, the compressor exhaust gas is controlled to enter a first target indoor unit in a running state through the first four-way valve for heat exchange, and the refrigerant after the heat exchange in the first target indoor unit is controlled to flow back to the compressor through the first four-way valve; The compressor exhaust gas is controlled to enter a second target indoor unit in a shutdown state through the first four-way valve, and the refrigerant flowing through the second target indoor unit is controlled to flow back to the compressor through the second four-way valve; The first port of the first four-way valve is connected with the exhaust port of the compressor, the second port of the first four-way valve is connected with one end of the heat exchanger of the indoor unit through an air pipe, the other end of the heat exchanger of the indoor unit is connected with the third port of the first four-way valve through a liquid pipe, the first electronic expansion valve is arranged on the liquid pipe between the indoor unit and the third port, the fourth port of the first four-way valve is connected with the suction port of the compressor through a gas branch, the first port of the first four-way valve is in internal communication with the second port, and the third port of the first four-way valve is in internal communication with the fourth port; The step of controlling the compressor exhaust gas to enter the first target indoor unit in a running state through the first four-way valve for heat exchange, and controlling the refrigerant after the heat exchange in the first target indoor unit to flow back to the compressor through the first four-way valve comprises: controlling the first electronic expansion valve corresponding to the first target indoor unit to be opened, so that the compressor exhaust gas enters the first target indoor unit through the first four-way valve and the air pipe, and flows back to the compressor through the first electronic expansion valve on the liquid pipe and the first four-way valve; The indoor unit comprises a first heat exchanger, a second heat exchanger and a second electronic expansion valve, the first electronic expansion valve is connected with the first heat exchanger through a pipeline, one end of the second electronic expansion valve is connected with the second heat exchanger through a pipeline, and the other end of the second electronic expansion valve is connected with the first electronic expansion valve and the first heat exchanger through a pipeline; The second heat exchanger is also connected with the first interface of the second four-way valve through high and low pressure pipelines, the second interface of the second four-way valve is connected with the suction port of the compressor through the gas branch, and the first interface of the second four-way valve is in internal communication with the second interface; The step of controlling the compressor exhaust gas to enter the second target indoor unit in a shutdown state through the first four-way valve, and controlling the refrigerant flowing through the second target indoor unit to flow back to the compressor through the second four-way valve comprises: controlling the first electronic expansion valve corresponding to the second target indoor unit to be closed, so that the refrigerant flowing into the first target indoor unit passes through the first electronic expansion valve on the liquid pipe and the first four-way valve to flow back to the compressor after passing through the first heat exchanger.

2. The start-up control method according to claim 1, characterized by Further comprising: controlling the second electronic expansion valve corresponding to the first target indoor unit to be closed, so that the refrigerant flowing into the first target indoor unit passes through the first electronic expansion valve on the liquid pipe and the first four-way valve to flow back to the compressor after passing through the first heat exchanger.

3. The start-up control method according to claim 1, characterized by The second four-way valve further comprises a third interface and a fourth interface, the third interface is connected with the exhaust port of the compressor, and the fourth interface is connected to the pipeline between the second interface and the gas distribution; the starting control method further comprises: determining whether the multi-connected air conditioner reaches a stable running state; when the multi-connected air conditioner reaches a stable running state, controlling the first electronic expansion valve corresponding to the first target indoor unit to be opened, controlling the second electronic expansion valve corresponding to the first target indoor unit to be opened, and controlling the second four-way valve to reverse, so that the first interface and the third interface are in internal communication, and the second interface and the fourth interface are in internal communication.

4. The start-up control method according to claim 3, characterized by Further comprising: when the multi-connected air conditioner reaches a stable running state, controlling the first electronic expansion valve corresponding to the second target indoor unit to be opened to a preset minimum opening degree, and controlling the second electronic expansion valve corresponding to the second target indoor unit to be opened to a preset minimum opening degree.

5. The start-up control method according to claim 3, characterized by The step of determining whether the multi-connected air conditioner reaches a stable running state comprises: monitoring the exhaust temperature of the compressor and the high-pressure saturation temperature, calculating the temperature difference between the exhaust temperature and the high-pressure saturation temperature, and determining that the multi-connected air conditioner reaches a stable running state when the temperature difference is greater than or equal to a second preset temperature.

6. A multi-connected air conditioner, characterized by comprising: Comprise: an outdoor unit, multiple indoor units and a controller, the outdoor unit comprises a first four-way valve and a second four-way valve, the controller comprises a computer readable storage medium storing a computer program and a processor, and the computer program is read and run by the processor to realize the method of any one of claims 1-5; the first port of the first four-way valve is connected with the exhaust port of the compressor, the second port of the first four-way valve is connected with one end of the heat exchanger of the indoor unit through a gas pipe, the other end of the heat exchanger of the indoor unit is connected with the third port of the first four-way valve through a liquid pipe, a first electronic expansion valve is arranged on the liquid pipe between the indoor unit and the third port, the fourth port of the first four-way valve is connected with the suction port of the compressor through a gas distribution, the first port of the first four-way valve and the second port are in internal communication, and the third port of the first four-way valve and the fourth port are in internal communication; The indoor unit comprises a first heat exchanger, a second heat exchanger and a second electronic expansion valve, the first electronic expansion valve is connected with the first heat exchanger through a pipeline, one end of the second electronic expansion valve is connected with the second heat exchanger through a pipeline, and the other end of the second electronic expansion valve is connected with the first electronic expansion valve and the first heat exchanger through a pipeline respectively; The second four-way valve comprises a first interface, a second interface, a third interface and a fourth interface; the second heat exchanger is connected with the first interface through a high-low pressure pipeline, the second interface is connected with a suction port of the compressor through the gas distributor, the third interface is connected with a discharge port of the compressor, and the fourth interface is connected to a pipeline between the second interface and the gas distributor; When the multi-connected air conditioner is started, the first interface and the second interface are internally communicated, and the third interface and the fourth interface are internally communicated; When the multi-connected air conditioner reaches a stable running state, the first interface and the third interface are internally communicated, and the second interface and the fourth interface are internally communicated.

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